As California suffers through another dry winter, increasing fears that drought conditions may be returning, the state’s residents are dropping conservation habits that were developed during the last drought and steadily increasing their water use with each passing month.

A new analysis of state water records by this news organization found California’s urban residents used 13.7 percent less water last year in the first eight months after Gov. Jerry Brown declared an end to the drought emergency than they used in the same eight-month period in 2013. But in each of those eight months last year, the water savings dropped from 20 percent in May to 2.8 percent in an unseasonably dry December.

“We are having a very dry winter again,” said Heather Cooley, water program director at the Pacific Institute, an Oakland non-profit that studies water use patterns. “That wet winter we saw last year could have been one wet winter in a 10-to-12 year drought period. We have to be very cautious about our water use.”

But it’s not clear Californians are getting that message. After last winter’s record rains, the governor on April 7 ended statewide emergency water conservation targets imposed on cities and water districts. Many eased, or dropped entirely, their mandatory water restrictions, rebate programs and other incentives to conserve, because they wanted to make more money by selling more water, and in part because it was difficult to convince their customers of the urgency when the state had just seen its wettest winter in 20 years.

But with each passing month, the savings have shrunk. Californians opened the spigots to water their lawns, took longer showers and returned to pre-drought habits, state records show.

By July, statewide water use was down 15 percent, then 8.5 percent in October. By December, the most recent month for which the State Water Resources Control Board has data, statewide water use was only down 2.8 percent, compared with December 2013, the baseline year that state water regulators use for monthly water conservation reports.

Usually after California droughts, some conservation is locked in permanently. That happened after the 1976-77 drought, the 1987-92 drought and the 2007-2009 drought.

People who install low-flush toilets or replace lawns with water-efficient landscaping don’t go back and remove them when it starts raining again, experts note. But as the memories of bone-dry conditions fade, it’s common for residents to use more water, and for cities and water districts to drop tough rules, and limit rebates, which cost them money.

In recent months, all of those trends have been underway. But very hot, very dry weather, particularly in Southern California, where temperatures this winter have reached the 90s in Los Angeles and rainfall levels are below 25 percent of historic averages, have quickly sped the return to heavier water use.

Meanwhile, the Sierra snow pack level on Tuesday was just 22 percent of its historic average. That’s lower than any Feb. 13 even during the worst years of the most recent drought, including 2015, when it was 26 percent on the same date.

That year, in the most stark depths of the drought, snow levels ended at 5 percent of normal on April 1, an all-time record low that led Brown that day to travel to a grassy meadow at Echo Summit near Lake Tahoe that should have been under five feet of snow and declare the first statewide mandatory water restrictions in California history, with a target of reducing urban water use by 25 percent — a goal the state nearly met.

“We’re in better shape this year with our reservoir levels,” said Felicia Marcus, chairwoman of the State Water Resources Control Board. “But if we don’t get any more snow — every day the news comes out that it’s dry and the high pressure ridge is upon us again — I just get more nervous and more nervous. We learned a big lesson in that drought. Let’s not forget it.”

Even though the drought emergency ended, the Brown administration required the state’s 410 largest cities, water districts and private water companies to continue reporting their monthly use to the state. The administration also kept in place water wasting rules, such as making it illegal to hose off sidewalks, wash cars without a hose nozzle or rent hotel rooms without notifying guests that they can choose not to have their sheets and towels washed every day.

Those water wasting rules, which carried fines of up to $500 for violators, lapsed in November when their emergency status expired. The state water board is scheduled to vote Feb. 20 to make them permanent, and two bills in the Legislature would give all cities the power to enforce them.

The news organization’s analysis shows that cities on the Central Coast saved the most water, 20.5 percent, in the May-December 2017 period, when compared with May-December 2013. Cities around the Bay Area saved 15.5 percent, and cities on in the South Coast region, mostly Los Angeles, San Diego and Orange County, saved the least, 11.7 percent.

Looking at individual communities, the Humboldt Bay Municipal Water District led the list, with a 56 percent reduction in water use in May-December, compared to the same period in 2013. But that’s because of a fluke: a local power plant near Eureka that is a major water user was not operating. Next up on the savings list was Santa Barbara, which cut use 43.2 percent, and has had far less rainfall than other parts of the state.

In the Bay Area, Menlo Park saved the most, cutting use 29.4 percent. The city continues to offer $125 rebates for people who buy low-flush toilets, along with paying $2 per square foot for people who remove lawns. It also has a water wasting hotline, and hands out free low-flow showerheads, faucet aerators and other gear at City Hall, and passed an ordinance last year requiring all large new commercial buildings to have dual plumbing to use recycled water for toilets.

“All the programs are still in place. Conservation is part of our water strategy,” said Azalea Mitch, Menlo Park’s city engineer.

Among the Bay Area’s largest water providers, San Jose Water Company, which raised its basic monthly service charge 26 percent and hiked its most commonly used tiered water rate 39 percent since June, 2016, reported a 22.5 percent reduction in water use from May-December 2017 compared to May-December 2013.

Contra Costa Water District cut by 19.2 percent, Santa Cruz by 19.5 percent, Palo Alto by 12.2 percent, San Francisco by 9 percent, Marin Municipal Water District by 8.9 percent and the East Bay Municipal Utility District by 12.1 percent.

Farther away, Los Angeles cut water use 9.1 percent and Sacramento, which still only allows residential lawn watering once a week until March 1, when it goes to twice a week, with fines of up to $500 for multiple violators, showed a 20.9 percent reduction.

“You can get a lot of water savings, even voluntary savings, if you give people the impression that it’s really important,” said Jay Lund, director of the UC-Davis Center for Watershed Sciences. “Most people try to be good citizens. They like to do their part. But if you don’t remind them, their mind goes to other things.”

Paul Rogers has covered a wide range of issues for The Mercury News since 1989, including water, oceans, energy, logging, parks, endangered species, toxics and climate change. He also works as managing editor of the Science team at KQED, the PBS and NPR station in San Francisco, and has taught science writing at UC Berkeley and UC Santa Cruz.

Leigh Poitinger is the News Research Director for the Bay Area News Group. She also coordinates the annual Wish Book program of The Mercury News. She began her career as a librarian at the Baltimore Sun.